The present invention relates to apparatus and methods for managing engine bleed air distribution and, more particularly, apparatus and methods for managing engine bleed air distribution based on consumer flow control.
In order to save weight, engine bleed air systems are designed with the thermal capacity to reduce the bleed air temperature to desired levels at typical, rather than worst case, operating points. In order to ensure that bleed air system overtemperature does not occur during abnormal or failure scenarios, a temperature protection function is required.
Typical temperature protection functions on conventional aircraft bleed air systems utilize the pressure regulation valve to limit the available pressure to consumer systems in order to reduce the level of hot side flow and thus the bleed system exit temperature. This method, although effective, penalizes all of the consumer systems equally when the performance of some may be more critical than others.
Other approaches that use the consumer systems to limit the hot side engine bleed flow rely on open loop limits to determine the level of flow consumption. These have the disadvantage of requiring conservative assumptions to be used for the condition based limits in order to ensure that overtemperature is avoided during the worst case scenarios.
As can be seen, there is a need for a bleed system management scheme that may allow consumer systems to limit the consumer flow to meet a specified bleed system outlet temperature.